Dynamic url changing using javascript

We all have instances where we want to change the url without reloading the page. its easy and simple to do. just append '#' to the url
ie:

 window.location.hash = "test";
it will add http://whiteboard1900.blogspot.com/#test
at the end of the url.
or alternatively use:
window.location.href=window.location.href+"#testval=1";